Transcript Document

Read pages 545 - 550 of Hamblin for details on the tectonic
movements along Transform Boundaries.
Other Continental Transform Fault boundaries: Dead Sea, New
Zealand: the Southern Alps.
mantle plume
Far from Plate boundaries, the movement of
plates and earth’s internal heat together produce
a new set of landforms. These are produced at
the Hot Spots above the mantle plumes.
Latest addition to the theory: in 1963 from
observations in Hawaii. Volcanoes are
progressively older along the direction of plate
movement.
Hot spots do not drift with the plates.
They are rooted deep in the mantle.
The lava erupted here are different from
the ones produced at divergent plate
boundaries: derived from deep in the
mantle
Plumes rise from 400 -- 700 km below
Plumes carry materials of significantly
higher temperatures (200ºc) than the
mantle; ther rise from the base of the
mantle; they are driven by internal heat;
they lose heat with time (about 100
million years): temporary features.
(Read pages 586 - 598 of Hamblin, but
you may reduce the contents)
60 million years ago
Today
Iceland lies at the intersection of
Mid-Atlantic Ridge but also sits
on a mantle plume which makes
the volcanic material different
from the usual basaltic rocks of
the mid-oceanic ridges.
30 million years ago
(Read pages 41 - 42 of
Hamblin)
Plates and Plate Motion
Earth’s major features, rocks, structures can be understood
from the interactions of the plates in the tectonic system
1. Divergent margins: being pulled apart: marked by oceanic ridges
2. North and South American plates are moving westward: interacting with Pacific,
Juan de Fuca, Cocos, and Nazca plates
3. Pacific plate is moving NW: deep sea trenches in western Pacific basin
4. Australian plate, includes Australia, India and NE Indian Ocean: moving
Northward: produced Himalayan Ranges, Volcanic Arcs of Indonesia
5. African Plate, including Africa, SE Atlantic and W. Indian ocean: moving
Northward: colliding with Eurasian plate
6. Eurasian plate moving eastward
7. Antarctic plate: includes Antarctica and floor of Antarctic Ocean: surrounded
by oceanic ridges